Pressure driven dispensing appliances for dispensing a liquid, such as a beverage, typically beer, have long been known in the art. A pressurized gas, such as carbon dioxide, is injected into the container containing the liquid to be dispensed in order to increase the pressure in the vessel with respect to ambient. Dispensing of a liquid is then simply controlled by the actuation of a valve located on a dispensing duct to bring the liquid contained in the container in fluid communication with ambient. The pressurized gas is usually stored in a pressure vessel of varying sizes depending on the end application, keeping in mind that sufficient gas must be available to at least empty a full liquid container of its content. The gas content of a pressurized gas vessel depends on the capacity of the vessel, and on the pressure of the gas, which in turn depends on the wall thickness of the vessel. For high capacity kegs of 10 liters and more as are used in pubs, a large, separate pressurized gas bottle is used and each time connected to a new keg. On the other hand, for home appliances of lower capacity of about 3 to 10 liters as are becoming more and more appreciated by the consumers, the pressure vessel is usually integrated within the appliance body. For containers of relatively small capacity, it is quite easy to fit a relatively small gas cartridge as disclosed e.g., in EP149352, under sufficient pressure (e.g., a typical CO2 cartridge is loaded at a pressure of the order of 100 bar) to deliver sufficient overpressure to the container for the dispensing of the whole content thereof. Problems start to arise, when more gas is required for driving the dispensing of larger volumes of liquid out of a container, as larger pressure vessels are required either to increase the vessel's capacity, or to strengthen the walls to withstand higher pressures. Both options are detrimental to the cost and aesthetic of the appliance. It should be noted that, for a same pressure resistance, the wall thickness of a pressure vessel increases non linearly with the capacity of the vessel.
In order to reduce the size of the gas storing vessel for a given amount of gas, it has been proposed to adsorb gas, usually carbon dioxide, on a solid substrate such as activated carbon, silica gel, zeolite, and the like. WO99/47451 discloses a device for storing and dispensing carbonated beverages such as beer comprising a compartment containing an amount of activated carbon fibres having a relatively large internal and external surface area, for adsorbing and/or absorbing therein and thereon a relatively large amount of CO2 at an acceptable gas pressure. Similarly, U.S. Pat. No. 4,049,158, WO2009/142977, U.S. Pat. No. 3,096,000, and WO2006/086932, disclose dispensing appliances storing propellent gases on various types of adsorbents. All the foregoing appliances have a drawback in common with most small size pressurized gas vessels, in that they are disposable and must be replaced with each new container, which increases substantially the cost of use of such appliances by the end-consumer
US2003136261 suggests to re-fill the gas storage compartment with a tablet, pellet or a ball of condensed firm phase CO2 (so-called-“dry ice”), which is not quite suitable for home applications. WO2005/070788A and WO2008/053215 disclose the use of a one-way valve to allow the introduction of carbon dioxide in to the solid/gas compartment prior to use, and during use of the system. This requires a source of pressurized CO2, which is normally available to the public only in pressurized bottles, which need be bought, stored, and refilled at specific places.
The present invention proposes a solution for a liquid dispensing appliance requiring very little budget for the use thereof, other than the purchase of a new liquid container, which can dispense a liquid without need of any external electric power energy, so that it can be used outdoor, or stored in a fridge, without risk of short circuits due to condensation or a battery leaking onto food. These and other advantages of the present invention are described in the following sections.